1. Field of the Invention
The present invention relates to an information processing system for controlling the utilization of digital contents, a medium, an information processing apparatus, an information processing method, and a storage medium storing a computer readable program for realizing such a method.
2. Description of the Related Art
There are recent rapid advancements on preparation and maintenance of optical fiber networks in a backbone communication network, propagation of cable television systems, practical use of satellite communications, propagation of local area networks, and the like. Interconnection of communication networks is vigorously progressing. Digital contents can be exchanged worldwide via such communication networks. The digital contents include character data, audio data, still image data, moving image data, computer programs and the like.
Since a digital content is made of digital information, the digital content can easily be copied. Digital contents pose a problem of copyright protection.
In order to deal with this problem, techniques called “electronic watermark” are used. The “electronic watermark” is techniques of processing a digital content in a predetermined manner to embed optional information in a digital content. The embedded information is hereinafter called “electronic watermark information”.
If copyright information is embedded in a digital content as the electronic watermark information by utilizing the electronic watermark techniques, the digital content and copyright information can be processed independently so that the copyright can be protected reliably.
A digital content embedded with electronic watermark information is received at a terminal such as a personal computer via, for example, an arbitrary communication network. If a user of a personal computer activates a preinstalled program for sampling or deriving electronic watermark information, the electronic watermark information can be sampled from the digital content. In other words, the electronic watermark information can be sampled if a user wishes to activate the sampling program.
If a malicious user utilizes a digital content without activating the sampling program or utilizes the digital content in the environment where the sampling program cannot be activated, the function of copyright protection cannot be realized because the electronic watermark information cannot be sampled from the digital content.